This invention pertains generally to a wheeled conveyance, such as a shopping cart, a luggage cart, a utility cart, a wheel chair, a gurney, or a tricycle, of a type having a metal chassis and wheels and designed to be manually moved by pushing, pulling, or pedaling along a supporting surface. This invention pertains specifically to an improved, static-dissipative member, which grounds the metal chassis to the supporting surface.
When a wheeled conveyance of the type noted above is moved along a supporting surface, such as a floor, the wheels may isolate the wheeled chassis electrically from the supporting surface. Thus, static discharges can occur, which may be bothersome if the wheeled conveyance is a shopping cart, a luggage cart, or a utility cart, but which may be hazardous if the wheeled conveyance is a gurney bearing a patient in a medical facility.
To minimize static discharges, it is known to use conductive, carbon-filled, or metal powder-filled polymers to make surface-engaging tires of the wheels. However, it is understood that wheels having surface-engaging tires made from such polymers, when dirty after extended periods of heavy use, nonetheless may isolate the wheeled chassis of a wheeled conveyance of the type noted above from the supporting surface.
Furthermore, it is known to use a metal chain to ground the wheeled chassis of a wheeled conveyance of the type noted above from the supporting surface. The metal chain is hung from the wheeled chassis so as to drag along the supporting surface when the wheeled conveyance is moved along the supporting surface. However, a metal chain is disfavored because a metal chain tends to damage the supporting surface, particularly if the supporting surface is a finished surface of a vinyl, wooden, or laminated floor.
This invention is applicable to a wheeled conveyance of a type designed to be moved by pushing, pulling, or pedaling along a supporting surface. As examples, which are not limiting, the wheeled conveyance may be a shopping cart, a luggage cart, a utility cart, a wheel chair, a gurney, or a tricycle. As examples, which are not limiting, the supporting surface may be a finished surface of a vinyl, wooden, or laminated floor.
The wheeled chassis has a metal chassis and has wheels, which support the metal chassis above the supporting surface, and which may isolate the metal chassis electrically from the supporting surface. This invention is applicable whether or not a conductive, carbon-filled, or metal powder-filled polymer is used to make surface-engaging tires of the wheels. The metal chassis is grounded to the supporting surface by an elongate member, which is arranged to drag along the supporting surface when the wheeled conveyance is moved along the supporting surface.
As improved by this invention, the elongate member is made from a non-metallic, static-dissipative material, at least where the elongate member drags along the supporting surface. Preferably, the non-metallic, static-dissipative material is a polymeric material, such as polyvinyl chloride. Preferably, the elongate member is a tubular, flexible member.
In a preferred embodiment of this invention, if each wheel of the wheeled conveyance has an axle, about which such wheel is rotatable, the elongate member is mounted mechanically and electrically to the axle of one of the wheels. This invention is applicable whether each wheel has its own axle or whether paired wheels have a common axle.
Furthermore, as contemplated by this invention, mounting of the elongate member electrically and mechanically to the axle of one of the wheels may be also applicable if the elongate member is a metal chain.